Hydrocarbon coking



Patented Dec. 21, 1948 HYDROCARBON COKING August Henry Schutte, Hastings on Hudson, N. Y., assignor to The Lummus Company, New York, N. Y., a corporation of Delaware Application September 28, 1944, Serial No. 556,261

13 Claims.

This invention relates to treating hydrocarbons and, in particular to the treatment of heavy oils.

It is the particular object of this invention to provide a new and improved method, and apparatus, for treating such oils, and particularly residues and/or by-products of petroleum refining, cracking, etc., whereby they are readily and conveniently converted to coke.

It is a further object of this invention to provide such a new and improved method which is continuous, and wherein heavy oil is converted into coke and vaporous products by introduction, in droplets, into a burning column of combustion air and other vapors and gases having coke particles suspended therein in disperse phase, the particles being retained and recirc'ulated in the suspension until they grow beyond a predetermined size, and the supply of combustion air to the burning column being so controlled as to maintainthe combustion partial (i. e., insufflcient air for complete combustion) It is a further object of this invention to provide such a method wherein the vaporous products of the aforesaid coking reaction are withdrawn from the aforesaid burning column, separated from coke fines, and subjected to a soaking operation. without addition of heat, for sufllcient time to allow completion of reactions (i. e., Cracking, etc.) therein, a part being withdrawn as production, and a part being returned to, or recycled through, the burning column.

It is a further object of this invention to provide apparatus particularly adapted to the accomplishment of the aforesaid method and above enu-l v vaporous by-products of the coking operation.

These and other objects and advantages of the invention will clearly appear from the following description taken with the drawing and the appended claims.

In the drawing, showing diagrammatically one illustrative form of apparatus for achieving the principles of this invention. a'reactor, generally 1 designated I, is provided which forms a chamber 1 `roviding superposed communicating elutrlator or reaction section 2 and coke collection section 3.

The elutriator orreaction section 2 comprises an elongated upwardly fiared, upwardly divergent, or downwardly convergent chamber portion communicating with the coke collectionchamber 3 through the throat portion 4.

Supply means 6 communicating with a supply of heavy oils, bottoms, tars or residues at suitable temperature, preferably from 875 F. to 900 F., terminates in a suitable distributor 6 disposed in the lower portion of the reaction or elutriator section 2 adjacent the throat 4 and distributes the charge in the form of droplets in the upwardly moving column of gases, coke particles, etc., as hereinafter described.

Adjacent the charge distributor 6, an air inlet 'I for fresh or make-up air communicates with the elutriator or reaction section 2 and supplies air thereto from the air blower under control of the valve la.

A coke outlet 9 leads from the lower end of the coke collection section to a coke cooler lil which receives the production coke and cools it to suitable temperatures before it is discharged through feeder ll and outlet I? to a suitable collection station as, for instance, a briquetting device, a I

chain grate, or a storage chamber or station.

Water is supplied through inlet l4 to coke cooler lil and converted to steam in the cooler IO, being withdrawn as steam through the outlet i l5 and conveyed to any desired point of use.

Leading from the upper end of the elutriator section 2 is the Vapor outlet IG which conveys overhead vapors and coke fines to a separator I l, preferably of the Cyclone type, Which separates the solids comprising the coke fines from the vapors. The vapors are passed through the Vapor outlet IS of the separator I'I to the oil Vapor soaking chamber I9 where they are retained for sufficient time, without addition of heat, for occurrence of, or completion of, reactions such as craoking therein. The solids (coke fines) are sent through the solids outlet 20 of the separator I'I. under control of the valve or damper 2I, to the main blower duct 422.

The main blower duct 22 communicates with the main blower 23 having its inlet 24 connected supplied either directly to the reaction section or elutriator section 2 under control of the valve 'Ia. as described above, or supplied in admixture with the vapors and dry coke fines in the main blower I duct 22 under control of the valve 26.

A valve 21 is provided for controlling the dev livery from the main blower duct 22 to the coke from 20% to 30% vapor and from 70% to 80% liquid. About 60% of the charge being vaporized in the elutriation section 2, the remainder in the form of heavy tar must be coked by the application of sufficient thermal energy to convert it into.

solid coke; this is accomplished through the combustion maintained throughout the chamber 2, 3.

Since the elutriator section 2 provides a diverging passage for the vapors and coke fines passing upwardly through the throat 4,1the velocity of the vapors and fines decreases during their upward travel. By controlling the size of the droplets or particles in which the charge is supplied to and above 515 inch diameter, for instance, while controlling the supply of air through inlet 'l and of vapors and fines through the main blower duct 22 (from soaking chamber I9 and separator IT), the velocity and combustion in the elutriator section can be so controlled as to produce in the elutriator section a temperature between 900 F. and 1500 F. and a column of gases and fines in motion, the Afines being of such size as readily to accommodate coking by acting as neuclei for further coke deposit resulting in their growth to production'coke size. The deposit of coke will increase their weight and size and cause them, upon growth to product size. to fall out of suspension into the coke collection section for removal as described above. Those fines which are sufiiciently buoyant to be carried over to the separator are returned or recycled and subjected to further growth upon their return, i. e., by collision with oil and coke particles under combus- 'tion in the column which causes further coke deposit and growth.

These fines (coke particles) of lesser size and weight which remain in suspension in the overhead vapors are removed through outlet it to the separator I 'I whence they are returned or recycled through solids outlet 20 and main blower duct 22 to the uprising column of fines suspended in vapors, where, upon sufcient increase in size and/or weight, they fall into the coke collection chamber 3 to become production coke.

Consider from another aspect, the variation and control of velocity in the burning column achieved through the upwardly divergent elutriator section, forms of the reaction or elutriator section, a separator which retains in this reaction chamber for further coking treatment, drying, or growth, those particles which are insuciently buoyant to pass over to the separator l'l and yet below production coke size. At the same time, by operation of this separator, those coke particles which are of production coke size and quality are separated out of the suspension and delivered by gravity to the coke collectionl charnber 3. The fines which are sumciently buoyant to pass over to the separator (and which are naturally below production coke size) are recycled 4 through the buming column for further coking. treatment and growth.

The term heavy oils" as used herein is to be broadly interpreted as covering hydrocarbons and oils of various specifications which may be vconverted into coke; the term embraces residues and residuals from topping processes and distillation processes and tars and other by-products of hydrocarbon cracking processes, etc.

In coking a 12.5 A. P. I, oil charge, supplied at the rate of 4,000 bhi/day or 57,400 lb./hr., the coke production equals approximately 12.2% (approx.) of the charge weight or (approx.) where the above described apparatus and method are used.

In coking such a charge the conditions are as follows:

Reaction temperature (in 2) 1,400 F. I Vapor outlet temperature (in ili) 1.400 F. Recirculation temperature (in 22) 1,200 F.

Requisite minimum velocity (at throat 4) for operation-(i. e., elutriationi in 2) 61/2 feet per second Minimum time of residence at 1,400 F.

(in 2) for heat transmission (i. e., conversion of oil particles to coke particles) 22 sec. Oil charge (in 5) at '900 F.,

35% vapor 57,400 lb./hr. Size of oil particle on admission to chamber (2) 'r in. diameter Air (in '|)=248,000 cu.

ft./hr 19,500 lb./hr.

Oil vapors produced (in ili) 50,400 lb./hr.

F'lue gas, produced (in l8) 20,900 lb./hr. Coke (in 9) 7,000 lb./hr Minimum size of collected coke particles (in 3) 1/64 in. diameter Where- Height of reaction section (2)=105 ft. Area of reaction section (at 4):51 sq. ft.

. coking method and apparatus for achieving the above stated objects and advantages as well as other advantages apparent to those skilled in the art.

It is, of course, to be understood that the above description is merely illustrative and in nowise limiting and that I desire to comprehend within my invention such modifications as are included within the scope of the following claims.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The method of coking heavy oil comprising, injecting particles of said oil into a generally upwardly moving current of heated gases and vapors in a confined spa-ce while supplying suficient combustion air for partial combustion, burning part of the contents of said space for converting said oil particles into coke particles, and controlling the velocity of' said contents of said space in such manner that coke particles above a predetermined size drop out of the contents of said space for collection as production coke while :mumoo drawing of! coke particles below a predctermined size from the upper portion o f said space.

2. The method of continuously coking heavy oil comprising forming a suspension by continuously iniecting particles of said oil into an upwardly moving current of gases undergoing combustion in a confined space while supplying sufficient combustion air only to render said suspension .capable of partial combustion to convert said oil particles into coke, and controlling the velocity of said suspension in such manner that coke particles above a predetermined size drop out of said suspension for collection as production coke while drawing od part of said coke particles below a predetermined size from the 'upper part of said suspension, a pair of the coke particles being eontinuously moved in said suspension.

3. The method of continuously treating heavy oils comprising injecting particles of said oii into an upwardly moving current of gases undergoing combustion in an upwardly expanding space while supplying sumcient air to form a suspension capable of partial combustion to convert said oil particles into coke, and controlling the velocity of said suspension in such manner that coke particles above a predetermined size drop out of said suspension for collection as production coke while particles below said predetermined size are continuously subjected to the effect of combustion gases and the oii whereby these below sized particles can increase to the predetcrmined size.

li. The method defined in claim 2 wherein portion of fine coke particles below said predetermined size are continuously removed i'ro said suspension and recycled therethrough for further growth to production coke Isize.

5. The method defined in claim 2 wherein the velocity of said upwardiy moving current deereases progressiveiy with the height of said conflned space to provide separation of fine buoyant coke particles from the larger coke particles in said space.

6. The method defined in claim 3 wherein the coke particles below said predetermined size are continuously removed from said burning suspeno sion with vaporous products of the coking reaction, then separated from said vaporous products and recycled to said burning suspension for growth to production coke size.

7. The method of continuously coking heavy oil comprising continuously injecting upwardiy. particles of said oil at approximately adik F. into an upwardly moving current of burning gases and air at from 900 F. to 1500" F. in a confined elu- 7triator chamber to form a suspension, maintaining said particles in said chamber for a suflicient time to convert said particles into coke, and controlling the velocity of said suspension in suci'i manner that coke particles above a predetermined size drop out of said suspension for collection as production coke and so that a pari; of the coke particles below such size are carrie4 ;it of the chamber.

8. The method defined in claim '7 wherein oil particles comprise droplets of appronimate 311; inch diameter, and wherein the minimum time of retention in said chamber is 22 seconds.

9. The method defined in claim 7 wherein said oil particles comprise droplets of approximately nleinch diameter and from 20% to 35% Vapor content upon admission to said chamber, wherein the time of retention in said chamber is at least 22 seconds, and wherein theminimum production coke particle size is l/s inch diameter.

10. The method of continuously coking heavy' vai? oil, comprising forming a suspension by continuously injecting ``particles of said oil into an upvwardly moving current of gases undergoing combustion in a confined space while supplying sufficient combustion air only to render said suspension capable of partial combustion to convert said oil particles into coke, controlling the velocity of said suspension in such manner that coke particles above a predetermined size drop out of said suspension for collection as production coke. continuously removing a part of the dry coke partlcles below said predetermined size from said burning suspension with vaporous products of the coking reaction, separating said below-size coke particles from said vaporous product and returning said below-size coke particles to said burning suspension for growth to production coke size, soaking said vaporous products of the coking reaction for conversion and withdrawing a part of said soaked vaporous products While returning the remainder of said soaked vaporous products to said upwardly moving current.

ll. In apparatus for coking heavy oils, 'a reactor having therein a chamber forming a coke collection section and an elutriator section thereabove, means for supplying heavy oil particles to said chamber, and means for controllably supplying combustion air and hot vapors to said chamber for forming a partially burning upwardly moving suspension with said oil, means for controlling the velocity of said suspension in said elutriator section for retention therein of coke particles above a predetermined size whereby flner coke particles only may pass over with the productl vapors from said elutriator section, means for separating said fine coke particles from said product vapors, a Vapor soaking chamber receiving and retaining the separated vapors for completion of reactions therein without addition of heat, and means for recirculating said fine coke particles through said burning suspension with a portion. at least,` of the output of said soairing chamber.

12. lin apparatus for coking heavy oils, a reactor having therein a chamber forming` a coke collection section and an eiutriator section thereabove, said sections being joined by a throat. means for supplying heavy oil particles to said elutriator section above the throat, means for supplying combustion air and hot vapors to said elutriator section for forming a burning, upwardly moving, partially combustible suspension with said oil, valve means for controlling the velocity of said suspension in said elutriator section for retention therein of coke particles above a predetermined sizehwhereby finer coke particles only may pass over with the product vapors from said elutriator section, the size of the throat and the velocity of combustion air being insufflcient to carry larger coke particles, whereby said larger coke particles drop through the throat into the coke collection section, separating means for sepsaid fine coke particles and said product rapors, soaking means for receiving and retaining said separated product vapors for completion of reactions therein, means for withdrawing a portion of the output of said soaking means as production, and means for supplying the remainder of said output to the burning suspension' in said. elutriator,

13. in apparatus for coking heavy oils, a reacter having therein a chamber forming a coke collection section and an elutriator section thereabove, means for supplying heavy oil particles to said chamber, and means for controllably supanonas plying combustion air and hot vapors to said chamber for forming a partially burning, upwardly moving suspension with said oil, means for controlling the velocity of said suspension in said elutriator section for retention therein of coke partlcles above a predetermine`` size whereby finer coke particles only may pass over with the product vapors from said elutriator section, means for separatlng said fine coke particles from said product vapors, and means for recirculating said fine coke partlcles through said burning sus= pension with a portion, at least, of the product vapors.

i AUGUST HENRY SCHUTTE.

. REFERENCES CHED The following references are of record in the flle of this patent:

Number Number 8 UNITED STATES PATENTS Name Date Bartling Mar. 31, '1931i Szikla et al. Aug. 2, 1932 Loomis May 30, 1933 Haultain Aug. 1, 1939 Malson Nov. 16, 1943 Potters Nov. 16, 1943 Heminger Nov. 7, 1944 Rollmax Dec. 26, 1944 Russell Dec. 26, 1944 FOREIGN PATENTS Country t Date Australia 1926 Austria June 25, 1927 

